An association study on Gilles de la Tourette's syndrome and catechol-O-methyl transferase gene polymorphism

Abstract

Objective To investigate the association between catechol-O-methyl transferase (COMT) gene polymorphism and Gilles de la Tourette’s syndrome(GTS). Methods Using Amplification Refractory Mutation System(ARMS) PCR genotyping assay method, a polymorphism (val158met) of COMT gene was genotyped in 112 of all GTS patients (total GTS group) including 54 GTS-alone patients group, 48 GTS+ ADHD patients group among of them and 71 healthy controls. The correlation between positive association of polymorphism (val158met) of COMT gene in GTS and the age of onset in patients with GTS was also analyzed. Results Compared with healthy controls group, genotype of val158met did not differ in total GTS patients group or alone-GTS patients group (χ2=0.56, P=0.756; χ2=1.05, P=0.600 respectively). There was also no significant difference (P>0.05) in allele distribution of val158met in total GTS patients group or alone-GTS patients group compared with controls group respectively (χ2=0.18, P=0.669; χ2=0.29, P=0.593 respectively). However, genotype distribution of val158met was significantly different between GTS+ ADHD patients group and controls group(χ2=6.35, P=0.041). The frequency of the val allele of this locus was significantly higher in GTS+ ADHD patients group than those in controls group (χ2=5.49, P=0.019). The mean age of onset (6.80±1.54) in 36 children within GTS+ ADHD patients group with the val/val genotype of COMT gene val158met polymorphism was significantly earlier than the mean age of onset (8.04±1.54) in 12 children in val/val genotype(P=0.016). Conclusion Polymorphism (val158met) of COMT gene may be associated with GTS children with comorbid ADHD, which may play an important role to make the age of onset in children with GTS become earlier. Key words: Gilles de la Tourette's syndrome; Catechol-O-methyl transferase; Association analysis; Age of onset